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          <div class="quiz-container">
            <div class="quiz-header">
              <h1>MQ的原理是什么 - 交互式测验</h1>
              <p>检验你对文档内容的理解程度</p>
            </div>
            <div id="quiz-content">
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                    <div class="progress-bar">
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      <script>
        const quizData = [
  {
    "question": "在消息队列的“发布/订阅 (Publish/Subscribe)”模型中，一条消息是如何被处理的？",
    "options": [
      "消息被发送到一个特定队列，并且只能被一个消费者处理一次。",
      "消息被发送到一个主题 (Topic)，所有订阅该主题的消费者都会接收并处理这条消息。",
      "生产者直接将消息发送给指定的消费者，绕过了队列。",
      "消息被均匀地分发给所有消费者，但只有一个消费者能成功处理。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "发布/订阅模型的核心思想是一对多的消息广播。生产者将消息发布到一个中心“主题”，所有对该主题感兴趣的消费者（订阅者）都会收到这条消息的副本并进行处理。这与点对点模型（一个消息只有一个消费者）形成对比。",
    "source": "文档中「3. 消息队列的核心原理」-「消息分发」部分",
    "hint": "思考一下“发布”和“订阅”这两个词在现实生活中的含义，比如订阅报纸或杂志。"
  },
  {
    "question": "在消息的生命周期中，消费者成功处理完一条消息后，为什么通常需要发送一个“确认 (acknowledgment)”？",
    "options": [
      "为了对消息内容进行加密，确保传输安全。",
      "为了通知生产者消息已到达，以便生产者发送下一条消息。",
      "为了触发消息队列的背压机制，减缓消息生产速度。",
      "为了通知消息队列该消息已被成功处理，可以安全地从队列中删除，从而避免消息被重复投递。"
    ],
    "correctAnswerIndex": 3,
    "explanation": "确认机制是保证消息可靠性的关键环节。消费者发送确认信号，告知MQ“这条消息我已经成功处理完毕”。MQ收到确认后，才会将该消息从队列中永久删除。如果没有收到确认（例如消费者处理失败或崩溃），MQ会认为消息未被成功处理，并在稍后将其重新投递给其他消费者，确保消息至少被成功处理一次。",
    "source": "文档中「3. 消息队列的核心原理」-「消息确认和重试」部分",
    "hint": "想象一下签收快递的过程，那个“签收”动作在整个流程中起到了什么作用？"
  },
  {
    "question": "根据文档，一些消息队列系统（如 Kafka）是如何在保证高吞吐量的同时，提供一定程度的消息顺序保证的？",
    "options": [
      "通过为每条消息添加全局唯一的时间戳，并强制消费者按时间戳顺序处理。",
      "通过使用分区 (Partition)，确保在单个分区内的消息是严格有序的。",
      "通过强制所有消息进入单一队列，并由单一消费者处理来保证绝对顺序。",
      "通过事务机制将一批消息捆绑在一起，确保这批消息的原子性处理。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "全局严格的顺序保证会极大地牺牲系统性能和并行度。因此，像Kafka这样的系统采用了分区的策略作为一种权衡。它将一个主题（Topic）分为多个分区，只保证每个分区内部的消息是按照发送顺序存储和消费的，而不同分区之间的消息顺序则不做保证。这使得系统可以通过并行处理多个分区来极大地提高吞吐量。",
    "source": "文档中「3. 消息队列的核心原理」-「消息顺序」部分",
    "hint": "文档中提到了一种策略，它在“一个分区内”保证顺序，但在“不同分区之间”不保证。"
  },
  {
    "question": "当消费者的处理速度远远慢于生产者的发送速度时，文档中提到的哪种机制可以用来防止系统过载？",
    "options": [
      "背压 (Backpressure) 机制",
      "持久化 (Persistence) 机制",
      "重试 (Retry) 机制",
      "负载均衡 (Load Balancing) 机制"
    ],
    "correctAnswerIndex": 0,
    "explanation": "背压是一种重要的流量控制机制。当消费者（下游）的处理能力达到瓶颈时，它会向生产者（上游）传递一个“压力”信号，请求其减慢发送速度。这可以防止消息在队列中过度堆积，从而避免消费者或消息队列本身因资源耗尽而崩溃。",
    "source": "文档中「3. 消息队列的核心原理」-「流量控制」部分",
    "hint": "文档中描述了一个防止系统过载的机制，它的名字字面意思是“反向的压力”。"
  },
  {
    "question": "消息队列的“持久化 (Persistence)”机制主要解决了什么问题？",
    "options": [
      "确保消息在网络传输过程中不会被窃听。",
      "确保在消息队列系统重启或发生故障时，存储在队列中的消息不会丢失。",
      "确保每条消息都只被一个消费者处理一次。",
      "确保消息按照生产者发送的严格顺序被消费。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "持久化的核心目标是保证消息的可靠性。通过将消息写入稳定的存储介质（如磁盘），即使消息队列服务进程崩溃、服务器宕机或重启，这些消息也能够被恢复，而不会丢失。这是构建可靠系统的基础。而加密、消费模型和顺序保证是由MQ的其他机制负责的。",
    "source": "文档中「3. 消息队列的核心原理」-「消息存储和持久化」部分",
    "hint": "思考一下，如果消息只存在于内存中，当服务器突然断电时会发生什么？持久化就是为了解决这个问题。"
  },
  {
    "question": "在消息队列的体系结构中，负责从队列中接收并处理消息的组件被称为什么？",
    "options": [
      "生产者 (Producer)",
      "队列 (Queue)",
      "消费者 (Consumer)",
      "主题 (Topic)"
    ],
    "correctAnswerIndex": 2,
    "explanation": "根据文档中的基本概念定义，消费者是消息处理的终端。它的职责是从队列或主题中拉取（或被推送）消息，并执行相应的业务逻辑。生产者负责发送消息，而队列和主题是存储消息的容器。",
    "source": "文档中「1. 消息队列的基本概念」部分",
    "hint": "在一个“生产-消费”模型中，哪个角色是“消费”数据的一方？"
  },
  {
    "question": "以下哪种场景最适合使用消息队列的“点对点 (Point-to-Point)”模型？",
    "options": [
      "一个新闻发布系统，需要将新文章通知所有订阅了该频道的用户。",
      "一个订单处理系统，其中每个订单创建任务需要被分发给一个且仅一个后台工作进程处理。",
      "一个系统状态监控系统，需要将警报同时发送给日志系统、邮件系统和短信系统。",
      "一个社交媒体平台，当用户发布新动态时，需要通知所有关注者。"
    ],
    "correctAnswerIndex": 1,
    "explanation": "点对点模型的核心特征是“一条消息只被一个消费者处理”。这非常适合任务分发和负载均衡的场景，比如订单处理、支付请求等，可以确保一个任务不会被多个工作单元重复执行。其他三个选项描述的都是一条消息需要被多个下游系统或用户处理的场景，这正是发布/订阅模型的典型应用。",
    "source": "文档中「3. 消息队列的核心原理」-「消息分发」部分",
    "hint": "这种模型的关键特征是“一条消息只被消费一次”，常用于任务队列。"
  }
];
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            const totalQuestions = quizData.length;
            const answeredCount = userAnswers.filter(a => a !== null).length;
            const wrongCount = answeredCount - correctCount;
            const skippedCount = totalQuestions - answeredCount;
            const accuracy = totalQuestions > 0 ? Math.round((correctCount / totalQuestions) * 100) : 0;
            const errorRate = totalQuestions > 0 ? Math.round((wrongCount / totalQuestions) * 100) : 0;

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                '<div class="final-score-container">' +
                '<h2>答题报告</h2>' +
                '<div class="score-summary">' +
                '<div class="score-card">' +
                '<h3>得分</h3>' +
                '<p>' + correctCount + ' / ' + totalQuestions + '</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>正确率</h3>' +
                '<p>' + accuracy + '%</p>' +
                '</div>' +
                '<div class="score-card">' +
                '<h3>错误率</h3>' +
                '<p>' + errorRate + '%</p>' +
                '</div>' +
                '<div class="score-card score-details">' +
                '<table>' +
                '<tr><td>正确</td><td>' + correctCount + '</td></tr>' +
                '<tr><td>错误</td><td>' + wrongCount + '</td></tr>' +
                '<tr><td>未答</td><td>' + skippedCount + '</td></tr>' +
                '</table>' +
                '</div>' +
                '</div>' +
                '<div class="report-actions">' +
                '<button id="review-btn">回顾测验</button>' +
                '<button class="primary" onclick="location.reload()">再试一次</button>' +
                '</div>' +
                '</div>';

            let reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }
            quizContentEl.insertAdjacentHTML('beforeend', finalScoreHtml);
            document.getElementById('review-btn').addEventListener('click', reviewQuiz);
        }

        function reviewQuiz() {
            const reportEl = document.querySelector('.final-score-container');
            if (reportEl) {
                reportEl.remove();
            }

            document.querySelector('.quiz-body').style.display = 'block';
            document.getElementById('quiz-footer').style.display = 'flex';
            
            currentQuestionIndex = 0;
            loadQuestion();
            updateNavigationButtons(); // Ensure nav buttons are correctly displayed
        }

        // Event Delegation for options
        optionsListEl.addEventListener('click', (event) => {
            if (event.target && event.target.matches('li.option-item')) {
                // Check if the question has already been answered
                if (userAnswers[currentQuestionIndex] === null) {
                    const selectedIndex = parseInt(event.target.dataset.index, 10);
                    selectOption(selectedIndex);
                }
            }
        });

        prevBtn.addEventListener('click', goToPreviousQuestion);
        nextBtn.addEventListener('click', goToNextQuestion);
        hintBtn.addEventListener('click', showHint);
        
        // 初始加载
        loadQuestion();
      </script>
    </body>
    </html>
  